Rooftop Revolution: An Update on Residential Solar Energy

Residential solar energy is cheaper and more efficient than ever thanks to innovations in technology, financing and installation.


| January/February 2012



Rooftop Solar Panels

Solar energy providers have been quietly, continuously innovating their offerings, moving us ever closer to powering our lives with the renewable energy of the sun.

From devastating oil spills to tense political battles, fossil fuel-based energy seems to be a never-ending source of bad news. But as we’ve been focused on headlines about offshore drilling in the Arctic and soaring gas prices, solar energy providers have been quietly, continuously innovating their offerings, moving us ever closer to powering our lives with the renewable energy of the sun. The price of solar panels has gone down 30 percent since the beginning of 2010 and the solar industry grew 69 percent in the past year, according to the Solar Energy Industries Association. Along with rapidly advancing the technology of solar panels, industrious companies are also providing new ways to finance and install photovoltaic solar energy. For those of us who dream of a clean-powered future, there is hope: The solar energy revolution looks brighter than ever.

Residential Solar Energy System Preferences

Regardless of where we live, we can all plug in the same Energy Star appliance and expect similar results. This is not the case with rooftop solar energy. Photovoltaic (PV) installations are highly customized, and the orientation of your roof, the cost of your local electricity, and the incentives offered in your region all play a key role in determining the type and price of a PV system for your home. Along with the cost of the panels themselves, those considering the overall cost of a residential solar energy system must factor in the balance of system (BOS) components—inverters, wiring, mounting and racking equipment—and nonhardware factors such as sales, installation and permit fees. (The panels, inverters and labor are the most expensive parts of a PV system.) Although efforts are underway to standardize the permitting process, currently permitting costs vary from state to state and range from as low as $50 to as much as $1,000.

There are two types of PV: Crystalline silicon panels and amorphous or thin-film silicon. Crystalline panels, the rigid panels we most often associate with solar power, come in two varieties: Monocrystalline is the oldest, most efficient technology for energy conversion, but it’s difficult and expensive to manufacture. Polycrystalline panels have lower efficiencies, but they are cheaper to manufacturer and less costly than monocrystalline. Over the last few years, the cost to manufacture crystalline PV panels has dropped significantly thanks to advances in technology, lower raw material costs and increased manufacturing efficiencies. “In 2000, the average solar panel could capture 10 to 12 percent of the sunlight that hit it, but today medium- to high-quality panels capture 15 to 21 percent,” says Tor Valenza (aka “Solar Fred”), a solar energy advocate and communications strategist.

Amorphous or thin-film silicon solar cells are a relatively new technology that comes in rolls or on prefabricated panels. Thin-film technology offers advantages: Compared with crystalline, it is simpler and less costly to manufacture and typically performs better in partial shade; and it’s lightweight and can be seamlessly integrated with roofing shingles. However, thin-film has lower efficiencies—generally about half that of crystalline—which means the cells require more space for the same output. “People are excited about the potential for thin-film,” says John Rayfield, vice president of marketing at Nanosolar, a thin-film solar cell manufacturer. “All of the visionary projections for the future of solar—such as rolled-on solar panels or solar roof shingles—are in development. As with any product, development is driven by consumer adoption. These products must become cost-effective for residential applications, then we will see more suppliers and greater uses for them.” 

Manufacturers are using thin-film technologies in residential roofing products today, but they currently comprise a relatively small segment of the residential market. Nevertheless, it is a growing segment of the renewable energy certificate (REC) market, in which utility companies get valuable credits for providing a portion of their electricity from renewable sources, so the technology might become available to you via your utility company. Nanosolar is focusing on utility-scale projects larger than 1 megawatt in size. “Instead of selling our panels to thousands of individuals, Nanosolar sells to one power plant developer or utility customer, which in turn enables them to deliver solar energy to thousands of people,” Rayfield says. “In fact, the price of our panels for large commercial and utility-scale customers will soon rival energy produced from gas-powered energy plants—meaning the solar value proposition for the utility-scale market will become more compelling than fossil fuel.”

Is Now the Time to Buy Solar Panels?

PV systems are less expensive than ever before, but the rapidly advancing technology may make you wonder whether the panels you purchase today will be obsolete in the near future. Probably not, says Robert Nolan, a principal at NanoMarkets, a market research firm for emerging technologies. Although efficiencies have increased dramatically since the advent of solar panels, solar technology builds on itself; today’s panels won’t be obsolete anytime soon. “Efficiencies are going to increase incrementally, but the cost of solar panels has already dropped significantly. If you can afford solar, and it makes sense where you live, there is no reason to wait,” Nolan says.





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